Electric switch



April 18, 1933. cs. SCOTT ELECTRIC SWITCH Filed Aug. 5, 1930 I N VEN TOR. George Scuff A TTORNE Y.

Patented Apr. 18, 1933 GEORGE SCOTT, OF LONDON, ENGLAND, ASSIGNOR TO CHICAGO PNEUMATIC TOOL COMPANY, OF NEW YORK, N. Y., A CORPORATION OF NEW JERSEY ELECTRIC SVJZTCH Application filed August 5, 1930, Serial No. 473,205, and in Great Britain A'pril' l, 1930.

This invention relates to electric switches, particularly for use with portable machines and tools and more specifically to switches of the reversing type.

The invention further relates to electric switches as disclosed in the copending application of Leon F. Meunier and Clarence J. Dresser Serial No. 343,972, filed March 2, 1929.

According to the invention disclosed in the said prior specification, the switch has a single control member which is movable in two distinct senses, movement in one sense being for opening and closing the line, and movement in the other sense being for reversal.

The senses of movement are angular and axial.

Although a switch constructed according to the said prior specification is practically fool-proof because axial movement is impossible until the switch handle is first placed in or turned to the off position and during axial movement the handle cannot be turned to the on position until it has reached a predetermined position in such movement, it is possible to disconnect the plug connecting the cable to the switch while current is flowing.

The object of this invention is to provide a safety device on said switch whereby withdrawal of the said plug is impossible while current is flowing.

Accordingly therefore, in an electrical switch of the type set forth, the switch handle shaft is provided with an abutment member so disposed thereon that, when the switch is in running position and current is flowing, it contacts with a projection or the like mounted on the plug, thus making it impossible to withdraw said plug in an axial direction.

Angular movement of the switch handle to the off position frees the said abutment member from the projection on the plug and said plug may be withdrawn with safety.

In order that the invention may be fully understood, it will now be described with reference to the accompanying drawing in which Figure 1 is a plan view of one form of switch constructed according to this invention and showing the top plate removed, and Figure 2 is an end view of a complete switch.

The switch mechanism is similar to that described in he said prior specification except that the switch is made to suit threephase A. C. circuits, and when the circuit is broken, the switch breaks on all thre phases.

a, b, are the top and bottom plates respectively of the switch. 0 is the switch shaft which is adapted to be moved angularly and axially. (Z is the switch lever fitted to said shaft 0. e is a plug connecting the electric'65 cable to the switch, and said plug is adapted to be pushed into the female member f of the coupling and lockedtherein by means of the screw threaded collar 9. h is a projection formed on the plug 6 and disposed 7 away from the collar 9.

Mounted on the shaft 0 of the switch is a quadrant or arm hen the switch is in running position and current is flowing, the quadrant or arm j takes up a posit-ion behind the collar 9 and constitutes a barrier and renders it impossible to withdraw the plug 6 until the switch is in the off position and the obstruction offered by the quadrant removed.

When the switch is in the reverse position, the quadrant takes up a position behind the projection ]i and it is still impossible to withdraw the plug 6 until the switch is in the off position.

However, when the switch is in the off position, hat is, in the position shown in full lines in Figure 2, the quadrant is moved away from the projection 7L and collar g and theplug can be disconnected with safety.

With a switch as above described, it will be seen that it is impossible to disconnect the plug while current is flowing.

' I claim as my invention:

1. In combination, an electric switch, a power lead having a plug secured to said switch, a control shaft for said switch arranged for axial movement and having a 00 handle for actuating the same, said handle being movable to on position in at least two positions of axial adjustment of said shaft, an arm in the form of a quadrant on said switch handle, and means on said plug engaged by said arm to prevent withdrawal of the plug when said handle is in each of its on positions.

2. In combination, an electric switch, a power lead having a plug secured to said switch, a control shaft for said switch arranged for axial movement and having a handle for actuating the same, said handle being movable to on position in at leasttwo positions of axial adjustment of said shaft, and spaced abutments on said plug in position to be engaged by said arm when said handle is in on position in all positions of axial adjustment of said shaft.

3. An electric reversing switch comprising a casing having contacts therein, and a socket for a cable connection, a control shaft angularly movable to on position for said contacts in two positions of axial adjustment of said shaft within said casing, a plug for the cable connection to fit said socket, a collar on said plug having threaded connection with said casing at said socket for securing said plug in the latter, a projection on said plug in spaced relation to said collar, and means on said shaft for engagement either with said collar or with said projection when said shaft is moved to either of its on positions for preventing withdrawal of said plug.

4:. An electric reversing switch comprising a casing having contacts therein and a socket for a cable connection, a control shaft angularly movable to on position for said contacts in two positions of axial adjustment of said shaft within said casing, a plug for the cable connection to fit said socket, a collar on said plug having threaded connection with said casing at said socket for securing said plug in the latter, a projection on said plug in spaced relation to said collar, a handle on said shaft, and a quadrant on said handle for engagement with said collar or with said projection when said handle is moved to on position dependent on its position of axial adjustment for preventing withdrawal of said plu Signed by me at London, England, this 14th day of July, 1930.

GEORGE SCOTT. 

